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fscrypt: move fscrypt_prepare_symlink() out-of-line

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In preparation for moving the logic for "get the encryption policy
inherited by new files in this directory" to a single place, make
fscrypt_prepare_symlink() a regular function rather than an inline
function that wraps __fscrypt_prepare_symlink().

This way, the new function fscrypt_policy_to_inherit() won't need to be
exported to filesystems.

Acked-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20200917041136.178600-12-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
This commit is contained in:
Eric Biggers 2020-09-16 21:11:34 -07:00
parent c7f0207b61
commit 31114726b6
2 changed files with 50 additions and 52 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

39
fs/crypto/hooks.c
View File

@ -166,12 +166,43 @@ int fscrypt_prepare_setflags(struct inode *inode,
return 0;
}
int __fscrypt_prepare_symlink(struct inode *dir, unsigned int len,
unsigned int max_len,
struct fscrypt_str *disk_link)
/**
* fscrypt_prepare_symlink() - prepare to create a possibly-encrypted symlink
* @dir: directory in which the symlink is being created
* @target: plaintext symlink target
* @len: length of @target excluding null terminator
* @max_len: space the filesystem has available to store the symlink target
* @disk_link: (out) the on-disk symlink target being prepared
*
* This function computes the size the symlink target will require on-disk,
* stores it in @disk_link->len, and validates it against @max_len. An
* encrypted symlink may be longer than the original.
*
* Additionally, @disk_link->name is set to @target if the symlink will be
* unencrypted, but left NULL if the symlink will be encrypted. For encrypted
* symlinks, the filesystem must call fscrypt_encrypt_symlink() to create the
* on-disk target later. (The reason for the two-step process is that some
* filesystems need to know the size of the symlink target before creating the
* inode, e.g. to determine whether it will be a "fast" or "slow" symlink.)
*
* Return: 0 on success, -ENAMETOOLONG if the symlink target is too long,
* -ENOKEY if the encryption key is missing, or another -errno code if a problem
* occurred while setting up the encryption key.
*/
int fscrypt_prepare_symlink(struct inode *dir, const char *target,
unsigned int len, unsigned int max_len,
struct fscrypt_str *disk_link)
{
int err;
if (!IS_ENCRYPTED(dir) && !fscrypt_get_dummy_context(dir->i_sb)) {
disk_link->name = (unsigned char *)target;
disk_link->len = len + 1;
if (disk_link->len > max_len)
return -ENAMETOOLONG;
return 0;
}
/*
* To calculate the size of the encrypted symlink target we need to know
* the amount of NUL padding, which is determined by the flags set in
@ -207,7 +238,7 @@ int __fscrypt_prepare_symlink(struct inode *dir, unsigned int len,
disk_link->name = NULL;
return 0;
}
EXPORT_SYMBOL_GPL(__fscrypt_prepare_symlink);
EXPORT_SYMBOL_GPL(fscrypt_prepare_symlink);
int __fscrypt_encrypt_symlink(struct inode *inode, const char *target,
unsigned int len, struct fscrypt_str *disk_link)

63
include/linux/fscrypt.h
View File

@ -225,9 +225,9 @@ int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry,
struct fscrypt_name *fname);
int fscrypt_prepare_setflags(struct inode *inode,
unsigned int oldflags, unsigned int flags);
int __fscrypt_prepare_symlink(struct inode *dir, unsigned int len,
unsigned int max_len,
struct fscrypt_str *disk_link);
int fscrypt_prepare_symlink(struct inode *dir, const char *target,
unsigned int len, unsigned int max_len,
struct fscrypt_str *disk_link);
int __fscrypt_encrypt_symlink(struct inode *inode, const char *target,
unsigned int len, struct fscrypt_str *disk_link);
const char *fscrypt_get_symlink(struct inode *inode, const void *caddr,
@ -520,15 +520,21 @@ static inline int fscrypt_prepare_setflags(struct inode *inode,
return 0;
}
static inline int __fscrypt_prepare_symlink(struct inode *dir,
unsigned int len,
unsigned int max_len,
struct fscrypt_str *disk_link)
static inline int fscrypt_prepare_symlink(struct inode *dir,
const char *target,
unsigned int len,
unsigned int max_len,
struct fscrypt_str *disk_link)
{
return -EOPNOTSUPP;
if (IS_ENCRYPTED(dir))
return -EOPNOTSUPP;
disk_link->name = (unsigned char *)target;
disk_link->len = len + 1;
if (disk_link->len > max_len)
return -ENAMETOOLONG;
return 0;
}
static inline int __fscrypt_encrypt_symlink(struct inode *inode,
const char *target,
unsigned int len,
@ -793,45 +799,6 @@ static inline int fscrypt_prepare_setattr(struct dentry *dentry,
return 0;
}
/**
* fscrypt_prepare_symlink() - prepare to create a possibly-encrypted symlink
* @dir: directory in which the symlink is being created
* @target: plaintext symlink target
* @len: length of @target excluding null terminator
* @max_len: space the filesystem has available to store the symlink target
* @disk_link: (out) the on-disk symlink target being prepared
*
* This function computes the size the symlink target will require on-disk,
* stores it in @disk_link->len, and validates it against @max_len. An
* encrypted symlink may be longer than the original.
*
* Additionally, @disk_link->name is set to @target if the symlink will be
* unencrypted, but left NULL if the symlink will be encrypted. For encrypted
* symlinks, the filesystem must call fscrypt_encrypt_symlink() to create the
* on-disk target later. (The reason for the two-step process is that some
* filesystems need to know the size of the symlink target before creating the
* inode, e.g. to determine whether it will be a "fast" or "slow" symlink.)
*
* Return: 0 on success, -ENAMETOOLONG if the symlink target is too long,
* -ENOKEY if the encryption key is missing, or another -errno code if a problem
* occurred while setting up the encryption key.
*/
static inline int fscrypt_prepare_symlink(struct inode *dir,
const char *target,
unsigned int len,
unsigned int max_len,
struct fscrypt_str *disk_link)
{
if (IS_ENCRYPTED(dir) || fscrypt_get_dummy_context(dir->i_sb) != NULL)
return __fscrypt_prepare_symlink(dir, len, max_len, disk_link);
disk_link->name = (unsigned char *)target;
disk_link->len = len + 1;
if (disk_link->len > max_len)
return -ENAMETOOLONG;
return 0;
}
/**
* fscrypt_encrypt_symlink() - encrypt the symlink target if needed
* @inode: symlink inode